Any Signs of Life in Mars Extreme Radiation Would Be Buried Six Feet Under

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Mars
Courtesy of Andrea Luck (Flickr CC0)

It’s a pretty grim picture for those contemplating life on Mars. In addition to being a distant, freezing wasteland, it also has so much radiation that any life would be buried six feet under. For the average human being, this might seem like an obvious conclusion; after all, Mars has no ozone layer, and its surface is exposed to higher levels of cosmic radiation than Earth. But plenty of scientists still think life is possible on Mars.

Cosmic Rays and Mars

Cosmic rays are high-energy particles that travel through space and can penetrate the surface of any planet. They’re generated in various ways, but one of the most frequent sources is supernovae. For this reason, the cosmic ray production rate is expected to be much higher near star-forming regions such as the Orion nebula. On Earth, the atmosphere shields against the majority of the cosmic rays in the air. The atmosphere on Mars is fragile and therefore does not provide much protection at all. In fact, Mars’ atmosphere is about 100 times less dense than Earth’s, meaning there is about 100 times more radiation on Mars than on Earth.

How Much Radiation Is There on Mars?

The average Martian surface radiation dose is about 600 Sv (millisieverts) per year, almost 100 times higher than the average for Earth. On Earth, the average human is only exposed to 0.33 Sv (millisieverts) of cosmic radiation per year. This radiation of high-energy streaming from energetic events and solar flares such as supernovae can penetrate and destroy organic molecules and rock it encounters

The average Martian radiation level varies by location and changes over time, but it has been measured at over one millisievert per year in the equatorial regions. This is equivalent to the radiation experienced by astronauts on the International Space Station. Although the Mars mission is expected to be shorter than the ISS mission, it’s still not exactly a walk in the park.

Life on Mars: The Basics

Mars
Courtesy of Steve Knight (Flickr CC0)

For life to exist on Mars, there would need to be a source of liquid water like there is on Earth. Water is frozen at the Martian surface, but it is uncertain whether there’s enough of it to create a source of liquid water. Because Mars is a lot colder than Earth, the water would need to be in a state of liquid brine that can exist at low temperatures. The question is whether or not this could exist on Mars. Scientists think that it could, based on the water that is at the Martian surface. Scientists must also consider the potential for radiation damage to DNA in any possible life on Mars. The high radiation levels would kill any energy that is not protected from the radiation. Rovers found organic materials that can’t be taken as evidence of life. Evidence also shows that ionizing radiation may have altered those molecules.

Bacterial Protection From Radiation

Bacteria can survive at a wide range of radiation levels. One species of bacteria, Deinococcus radiodurans, can stay up to 5 Sv (millisieverts) of radiation. This is an incredibly high level of radiation for any form of life, and most other bacteria would be killed long before reaching this level. However, some species of bacteria have been shown to survive the high radiation levels on Mars. These bacteria have been exposed to radiation in labs, and some of them have been able to survive it. It’s important to note, however, that these experiments were done in a lab under much more controlled conditions than would be found on Mars. So while humans know that certain bacteria could survive on Mars, they don’t know how many of them would be needed to be present to sustain a population.

Humans Are Built to Withstand Heavy Radiation Exposure

Humans can be exposed to high levels of radiation and still be able to live an everyday, healthy life. There are limits to this, but experiments have shown that humans can survive up to 10 Sv (millisieverts) of radiation without significant long-term effects. This is enough to ensure that any human astronaut traveling to Mars will not be in danger from the radiation. In fact, space travelers are exposed to more radiation than Mars astronauts would be exposed to. When astronauts travel through the Van Allen belts, they are being exposed to much higher levels of radiation than they would be on the surface of Mars. The radiation levels on the surface of Mars are high enough to pose a risk for DNA damage, but it’s uncertain whether there would be enough damage to pose a significant health risk

Conclusion

Mars is a dangerous place, but they’ve found it can be much less lethal than people once thought. The high radiation levels pose real risks to life, but some types of bacteria have been shown to have natural defense mechanisms that can protect against it. Even if these bacteria are unable to survive the radiation, it is still possible for humans to live on Mars. The only question is how people will protect themselves from making the journey safe enough to survive long term. There’s no doubt that Mars is a challenging place to live, but they’ve found that it’s not impossible. The real question is whether they’re prepared to make the sacrifices necessary to make it a reality.

Written by Janet Grace Ortigas

Sources:

Scientist Alert: Mars Has So Much Radiation, Any Signs of Life Would Be Buried Six Feet Under; by Michelle Starr
Head Topics: Mars Has So Much Radiation, Any Signs of Life Would Be Buried Six Feet Under; by Michelle Starr
Mars | NASA: NASA Mars Exploration

Featured and Top Image Courtesy of Andrea Luck‘s Flickr Page – Creative Commons License
Inset Image Courtesy of Steve Knight‘s Flickr Page – Creative Commons License

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